Well I have heard lot about it ..that it is quite scalable and rich with unique features..
Most of the software industries are on with latest software products..Like Zyrion's Traverse,..which can not only monitor large multi-vendor networks but get real-time notifications on outages too..
Ye.. Traverse has an upper edge over Nagios as Traverse is a system and network monitoring software application that is built on a powerful, fully-distributed architecture featuring three primary components namely:
Data Gathering Engines (DGE)
Business Visibility Engine (BVE)
Business Visibility Engine Web UI
Nevertheless, Zyrion was selected as Network World Product of the Week...